Hepatoprotective activity of 1-(4-(Dimethylamino)Benzylidene)-5-(2-Oxoindolin-3-ylidene) Thiocarbohydrazone in rats

The aim of the present study was to evaluate the hepatoprotective activity of 1-(4-(dimethylamino)benzylidene)-5-(2-oxoindolin-3-ylidene) thiocarbohydrazone, a novel isatin derivative against carbon tetrachloride (CCl₄)-induced hepatotoxicity in rats. Hepatic damage was induced by administration of CCl₄ (1 ml/kg, b.w., p.o.) in combination with liquid paraffin (1:1) as a single dose. The hepatotoxic rats were treated with test compound at doses of 50 or 100 mg/kg for three days and liver damage biomarkers, including activities of serum glutamate pyruvate transaminase (SGPT), serum glutamate oxaloacetate transaminase (SGOT), serum alkaline phosphatase (ALP), and levels of total serum bilirubin (TB) measured in blood samples. Results demonstrated that treatment with test compound at doses of 50 or 100 mg/kg to hepatotoxic rats produced a significant dose-dependent reduction of elevated SGOT, SGPT, ALP activities and TB levels indicating a hepatoprotective effect that was confirmed by histopathological examination of liver tissues. The study results confirmed the hepatoprotective activity of 1-(4-(dimethylamino)benzylidene)-5-(2-oxoindolin-3-ylidene) thiocarbohydrazone in rats.     

Protective effect of kombucha mushroom (KM) tea on phenol-induced cytotoxicity in albino mice

The present study was carried out to evaluate the protective role of kombucha mushroom (KM) tea on cytotoxicity induced by phenol (PHE) in mice. We used weight gain and micronucleus (MN) frequency as indicators of cytotoxicity and supported these parameters with pathological findings. The animals were randomly divided into seven groups: (Group I) only tap water (Group II) 1000 microl kg(-1) b. wt KM-tea, (Group III) 35 mg kg(-1) body wt. PHE (Group IV) 35 mg kg(-1) body wt. PHE + 250 microl kg(-1) b. wt KM-tea (Group V) 35 mg kg(-1) b. wt PHE + 500 microl kg(-1) b. wt KM-tea (Group VI) 35 mg kg(-1) b. wt PHE + 750 microl kg(-1) b. wt KM-tea, (Group VII) 35 mg kg(-1) b. wt PHE + 1000 microl kg(-1) b. wt KM-tea, for 20 consecutive days by oral gavage. The results indicated that all KM-tea supplemented mice showed a lower MN frequency than erythrocytes in only PHE-treated group. There was an observable regression on account of lesions in tissues of mice supplemented with different doses of KM-tea in histopathological observations. In conclusion, the KM-tea supplementation decreases cytotoxicity induced by PHE and its protective role is dose-dependent.     

Alleviation of nickel stress by halophilic bacteria in mungbean(Vigna radiata)

Mungbean is an important, short-duration legume crop with high nutritive value for poor families, where protein and micronutrient scarcity are most pervasive. In developing countries, like Pakistan, where mungbean is one of the greatest sources of protein for underprivileged people, salinity and metal stresses are drastically limiting its yield. Therefore, it is necessary to explore the ways for promoting the growth of mungbean under stressed conditions. This study provides the basis for the use of two previously isolated halophilic and nickel-resistant bacteria [Bacillus subtilis and Halomonas aquamarina(1)] in promoting the growth of mungbean plant under nickel-stressed environments. These bacterial strains were previously found to improve the growth of plants under salinity because of their good biofilm-forming abilities. We hypothesized that these two halophilic and nickel-resistant biofilm-forming bacteria can help the plants to grow under nickel-stressed environments by promoting soil aggregation as they were previously reported to resist salinity and nickel stress, as well as were found to promote plant growth under saline environments. The results revealed that under nickel stress, both bacteria promote plant growth by facilitating the formation of soil aggregates through an increase in their extra polymeric substance(EPS) production.     

苯并(a)芘对鲫鱼(Carassius auratus)肝脏抗氧化酶的影响

研究了苯并(a)芘(BaP)暴露对鲫鱼肝脏抗氧化酶的影响．共设置4个处理组，浓度分别为每千克体重0．01mg、0．1mg、1mg和10mg，暴露方式采用腹腔注射，分别在暴露后6h、12h、48h和96h测定肝脏超氧化物歧化酶(SOD)、过靴氢酶(CAT)和谷胱甘肽过氧化物酶(GPX)活性．结果显示，所有暴露浓度对SOD活性明显抑制，各处理组活性在暴露后6h均低于对照组，在暴露后12h至48h有所回升，暴露后96h又降至对照水平以下．0．01mg kg^-1、0．1mg kg^-1处理组CA3、活性在暴露期间无显著改变，1mg kg^-1、10mg kg^-1处理组CAT活性在暴露后12h显著升高，暴露后96h回落至对照水平以下，此时10mg kg^-1处理组与对照组差异显著．对照组GPX活性在暴露后出现波动，0．1mg kg^-1处理组在暴露后96h显著低于对照组，而其它处理组活性与对照组在暴露期间无显著差异．结果表明，BaP能对鲫鱼肝脏抗氧化酶产生影响，多种抗氧化酶活性相结合可作为BaP暴露的生物标志物．图3参18     

Propetamphos enhances chlorpyrifos-induced organophosphate-induced delayed neurotoxicity (OPIDN) in Hens: a role for plasma butyrylcholinesterase

This study examined dose-response effects of chlorpyrifos (CPF) and propetamphos (PRO) on producing organophosphorus-induced delayed neurotoxicity (OPIDN) in hens. A single oral dose of 1, 3, 30, or 100 mg/kg of each compound was administered individually, or in combination to groups of 10 hens. Plasma butyrylcholinesterase (BChE) activity was inhibited by all doses of each individual compound. Chlorpyrifos alone or in combination with PRO resulted in decreased acetylcholinesterase (AChE) activity. No dose of CPF or PRO alone resulted in the inhibition of neuropathy target esterase (NTE) or produced OPIDN. In contrast, combined exposure to high doses of CPF and PRO produced diminished NTE activity and produced OPIDN. Brain NTE activity was decreased by 67% and 71% by combined treatment of 100 mg/kg CPF with 30 mg/kg and 100 mg/kg PRO, respectively, consistent with the development of ataxia and paralysis, characteristic of OPIDN. Only the highest dose of CPF 100 mg/kg interacted with the two highest doses of PRO to block NTE and induce OPIDN, whereas no marked interaction occurred at lower doses. Data indicate that PRO enhances the ability of high doses of CPF to produce OPIDN by binding to plasma BChE that appears to act as a buffering system to modulate the toxicity of CPF. In effect, the ability of BChE to bind to CPF is diminished by PRO, resulting in more CPF delivery to the brain, and subsequent development of OPIDN at a dose that does not initiate this effect by itself.     

EDTA and citric acid mediated phytoextraction of Zn, Cu, Pb and Cd through marigold (Tagetes erecta)

Phytoextraction is an emerging cost-effective solution for remediation of contaminated soils which involves the removal of toxins, especially heavy metals and metalloids, by the roots of the plants with subsequent transport to aerial plant organs. The aim of the present investigation is to study the effects of EDTA and citric acid on accumulation potential of marigold (Tagetes erecta) to Zn, Cu, Pb, and Cd and also to evaluate the impacts of these chelators (EDTA and citric acid) in combination with all the four heavy metals on the growth of marigold. The plants were grown in pots and treated with Zn (7.3 mg l(-1)), Cu (7.5 mg I(-1)), Pb (3.7 mg l(-1)) and Cd (0.2 mg l(-1)) alone and in combination with different doses of EDTA i.e., 10, 20 and 30 mg l(-1). All the three doses of EDTA i.e., 10, 20 and 30 mg l(-1) significantly increased the accumulation of Zn, Cu, Pb and Cd by roots, stems and leaves as compared to control treatments. The 30 mg l(-1) concentration of citric acid showed reduced accumulation of these metals by root, stem and leaves as compared to lower doses i.e., 10 and 20 mg l(-1). Among the four heavy metals, Zn accumulated in the great amount (526.34 mg kg(-1) DW) followed by Cu (443.14 mg kg(-1) DW), Pb (393.16 mg kg(-1) DW) and Cd (333.62 mg kg(-1) DW) in leaves with 30 mg l(-1) EDTA treatment. The highest concentration of EDTA and citric acid (30 mg l(-1)) caused significant reduction in growth of marigold in terms of plant height, fresh weight of plant, total chlorophyll, carbohydrate content and protein content. Thus EDTA and citric acid efficiently increased the phytoextractability of marigold which can be used to remediate the soil contaminated with these metals.     

Distribution of organo-chlorine pesticides (DDT and HCH) between plant and soil system

This paper reports a study of the distribution of organo-chlorine pesticides (DDT and HCH) between rice plants and the soil system by spraying before the heading stage at four different dosage levels--control, normal dosage (15 kg ha(-1) of 6% HCH and 7.5 kg ha(-1) of 25% DDT), double dosage and four times dosage. Soil and plant samples were taken respectively at the 1st h, 3rd, 10th, 20th, and 40th day after spraying and at the harvest time. The results indicate that less than 5% of HCH and 15% of DDT were absorbed by the surface of rice leaves for normal dosage. Most of both pesticides moved into the soil in solution after spraying. Compared with DDT, HCH was degraded and run off more easily. HCH residues in the surface soil layer (1-3 cm) were already below 6.4 microg kg(-1) at the mature stage, lower than Chinese Environmental Quality Standard for Agricultural Soils: HCH < 0.05 mg kg(-1). However DDT residues in the surface soil layer remained 172 microg kg(-1), higher than the national standard: DDT < 0.05 mg kg(-1). According to the test f OCP residues in rice seeds, it can be concluded that the OCP sprayed onto the surface of rice leaves can move into rice plants and accumulate in the seeds at the mature stage. HCH residues in rice seeds of the double and four times dosage treatments, and DDT residues in all treatments, exceeded the Chinese National Food Standard (HCH < 0.10 mg kg(-1), DDT < 0.20 mg kg(-1)).     

Influence of endosulfan and monocrotophos exposure on the activity of NADPH cytochrome C reductase (NCCR) of Labeo rohita (Ham)

The response of NADPH cytochrome C reductase (NCCR) activity in liver of Labeo rohita fish exposed to the pesticides, 0.25 microgl(-1) endosulfan and 2 mg/l monocrotophos was studied. In terms of specific enzyme activity (mU/mg protein) a significant level of NCCR was observed in the liver tissues of Labeo rohita exposed to the pesticides, when compared to the control fish (2.460 mU/mg protein). Increase of NCCR activity was more in the liver of the fish exposed to monocrotophos (4.595 mU/mg protein) than those exposed to endosulfan (2.850 mU/mg protein). The results demonstrate that the pesticides, endosulfan and monocrotophos, interfere with NADPH dependent monoxygenase mechanism and are effective inducers of NADPH cytochrome C reductase. The activity of NCCR in the liver tissue of Labeo rohita may serve as a useful tool for monitoring aquatic pollution.     

Chemical changes in agricultural soils of Korea: data review and suggested countermeasures

The monitoring of chemical properties, including heavy metals, in soils is necessary if better management and remediation practices are to be established for polluted soils. The National Institute of Agricultural Science and Technology initiated a monitoring study that investigated fertility and heavy metal contents of the benchmarked soils. The study covered paddy soils, upland soils, and horticultural soils in the plastic film houses, and orchard soils throughout the Korea from 1990 to 1998. Likewise, 4047 samples of paddy and 2534 samples of plastic house in 1999 and 2000 were analyzed through the Soil Environment Conservation Act. Soil chemical properties such as pH, organic matter, available phosphate and extractable calcium, magnesium and potassium contents, and heavy metal contents such as cadmium, copper, lead, zinc, arsenic, mercury, and cobalt contents were analyzed. The study showed that the average contents of organic matter, available phosphate, and extractable potassium rapidly increased in plastic house soils than in upland or paddy soils. Two kinds of fertilizer recommendation systems were established for the study: the standard levels by national soil average data for 77 crops and the recommendation by soil test for 70 crops. Standard nitrogen fertilizer application levels for cereal crops changed from 94 kg/ha in 1960s, 99 kg/ha in 1970s, 110 kg/ha in 1980s to 90 kg/ha in 1990s. The K2O-fertilizer also changed from 67 kg/ha in 1960s, 76 kg/ha in 1970s, 92 kg/ha in 1980s, and only 44 kg/ha in 1990s. In rice paddy fields, the average contents of Cd, Cu, Pb, and Zn in surface soils (0-15 cm depth) were 0.11 mg kg(-1) (ranged from 0 to 1.01), 4.70 mg kg(-1) (0-41.59), 4.84 mg kg(-1) (0-66.44), and 4.47 mg kg(-1) (0-96.70), respectively. In the uplands, the average contents of Cd, Cu, Pb, Zn, and As in surface soils (0-15 cm depth) were 0.135 mg kg(-1) (ranged from 0 to 0.660), 2.77 mg kg(-1) (0.07-78.24), 3.47 mg kg(-1) (0-43.00), 10.70 mg kg(-1) (0.30-65.10), and 0.57 mg kg(-1) (0.21-2.90), respectively. In plastic film houses, the average contents of Cd, Cu, Pb, Zn, and As in surface soil were 0.12 mg kg(-1) (ranging from 0 to 1.28), 4.82 mg kg(-1) (0-46.50), 2.68 mg kg(-1) (0-46.50), 31.19 mg kg(-1) (0.19-252.0), and 0.36 mg kg(-1) (0-4.98), respectively. In orchard fields, the average contents of Cd, Cu, Pb, Zn, As, and Hg in surface soils (0-20 cm depth) were 0.11 mg kg(-1) (ranged from 0-0.49), 3.62 mg kg(-1) (0.03-45.30), 2.30 mg kg(-1) (0-27.80), 16.60 mg kg(-1) (0.33-105.50), 0.44 mg kg(-1) (0-4.14), and 0.05 mg kg(-1) (0.01-0.54), respectively. For polluted soils with over the warning content levels of heavy metals, fine red earth application, land reconsolidation and soil amelioration such as lime, phosphate, organic manure, and submerging were recommended. For the countermeasure areas, cultivation of non-edible crops such as garden trees, flowers, and fiber crops; land reformation; and heavy application of fine red earth (up to 30 cm) were strongly recommended. Land use techniques should be changed to be harmonious with the environment to increase yield and income. Soil function characteristics should be taken into account.     

Pesticide effects on microbial population and soil enzyme activities during vermicomposting of agricultural waste

The effects of different pesticides (propiconazole, profenofos, pretilachlor) on vermicomposting were evaluated for the adverse effects on soil enzyme activities (dehydrogenase, phosphatase, urease) and total microbial counts (TMC). There were remarkable increase in enzyme activities and TMC in presence of earthworm compared to control (earthworm absent). In comparison to control, the activities of phosphatase, dehydrogenase and urease in presence of vermicompost increased upto 30, 128 and 31.3% respectively; whereas increase of TMC was 71.9%. But, in presence of each of the pesticide, said activities decreased. Maximum inhibition of soil phosphatase activity (46.6%) was observed in presence of propiconazole (100 mg kg(-1)) after 120 days. Profenofos affected the soil dehydrogenase activity in the tune of 47% at 1000 mg kg(-1) concentration after 80 days and thereafter, the extent of toxicity decreased little. Soil urease activity was affected markedly in presence of profenofos and was 62% at 1000 mg kg(-1) level after 80 days. TMC also declined in presence of profenofos and pretilachlor. Increase in TMC was about 71.9% compared to control and the inhibition was more or less 60% when profenofos (1000 mg kg(-1)) was present even after 120 days of treatment.     

Effect of manganese toxicity on pigment content,Hill activity and photosynthetic rate of Vigna radiata L. Wilczek seedlings

Effect of different concentrations, viz. 10(-4) M, 5 x 10(-4) M, 10(-3) M and 5 x 10(-3) M of manganese sulphate (MnSO4, 7H2O) on chlorophyll, carotenoid pigment content and photosynthesis of mungbean seedlings was examined Progressive increase in manganese sulphate concentration upto 5 x 10(-3) M brought about a progressive decrease in total chlorophyll and chl a content. Chl b content changed very little by excess manganese treatment. Total carotenoid pigment content decreased considerably in comparison to control with every concentration of manganese sulphate tried here. Hill activity of chloroplasts isolated from leaves of mungbean seedling and rate of photosynthesis in terms of CO2 uptake showed progressive reduction along with the increase in concentration of the manganese.     

全氟辛烷磺酸(PFOS)对三角帆蚌肝胰腺的氧化性损伤

PFOS是典型的持久性有机污染物,迁移能力强,具有较高的生物可利用性和蓄积能力,且具有广泛的生物毒性。为探究PFOS对淡水底栖生物的毒性作用机制,以三角帆蚌为研究对象,进行了不同剂量(0.1、1.0、5.0 mg·L-1)的PFOS胁迫和净水恢复实验,期间对受试生物肝胰腺中的谷胱甘肽(GSH)含量、谷胱甘肽-S转移酶(GST)活性、超氧化物歧化酶(SOD)活性,以及谷丙转氨酶(ALT)和谷草转氨酶(AST)的活性进行了连续测定。结果发现,低浓度胁迫(0.1 mg·L-1)对各项指标均有不同程度的诱导作用,且持续时间较长;而在中高浓度PFOS胁迫下,则呈现出明显的诱导向抑制过渡的时间效应。GSH含量和GST活性具有较高的相关性(P0.05)。恢复实验中,所测指标普遍未恢复到对照组水平,说明P FOS胁迫损伤的恢复需要更长的时间。研究表明,PFOS对三角帆蚌肝胰腺的氧化胁迫显著,并能快速地激活肝胰腺细胞的解毒代谢;但长期的PFOS胁迫则会造成肝胰腺细胞的实质性损伤。     

Role of phosphate solubilizing bacteria on rock phosphate solubility and growth of aerobic rice

Use of phosphate-solubilizing bacteria (PSB) as inoculants has concurrently increased phosphorous uptake in plants and improved yields in several crop species. The ability of PSB to improve growth of aerobic rice (Oryza sativa L.) through enhanced phosphorus (P) uptake from Christmas island rock phosphate (RP) was studied in glasshouse experiments. Two isolated PSB strains; Bacillus spp. PSB9 and PSB16, were evaluated with RP treatments at 0, 30 and 60 kg ha(-1). Surface sterilized seeds of aerobic rice were planted in plastic pots containing 3 kg soil and the effect of treatments incorporated at planting were observed over 60 days of growth. The isolated PSB strains (PSB9 and PSB16) solubilized significantly high amounts of P (20.05-24.08 mg kg(-1)) compared to non-inoculated (19-23.10 mg kg(-1)) treatments. Significantly higher P solubilization (24.08 mg kg(-1)) and plant P uptake (5.31 mg plant(-1)) was observed with the PSB16 strain at the highest P level of 60 kg ha(-1). The higher amounts of soluble P in the soil solution increased P uptake in plants and resulted in higher plant biomass (21.48 g plant(-1)). PSB strains also increased plant height (80 cm) and improved root morphology in aerobic rice. The results showed that inoculation of aerobic rice with PSB improved phosphate solubilizing activity of incorporated RP.     

伊维菌素对雄性吉富罗非鱼生理生化指标的影响

为探讨抗寄生虫药物伊维菌素(IVM)对鱼类的毒性效应,以雄性吉富罗非鱼(Oreochromis niloticus)为实验对象,设定了A(空白对照)、B(乙醇对照)、C(0.1 mg·kg~(-1))、D(0.5 mg·kg~(-1))、E(1 mg·kg~(-1))5个实验组,研究IVM对吉富罗非鱼肝脏和血液生理生化的影响。研究发现:正常生理状态下吉富罗非鱼肝脏中的丙二醛(MDA)含量较低,IVM作用后除最高剂量E组中MDA含量在4 h、16 h和24 h时极显著高于对照组外,其余各组均未受到显著影响。较低注射剂量C组中超氧化物歧化酶(SOD)活性均得到了诱导,且均显著高于对照组,较高注射剂量组中除E组在第4 h、16 h和24 h SOD活性显著高于对照组外,其余均未发现有显著变化。肝脏中谷草转氨酶(AST)和谷丙转氨酶(ALT)在IVM作用下均发生了一定的变化,尤其是E组均显著低于对照组。与肝脏中的相反,血液中的AST则随剂量的升高而呈现增加的趋势,在某些时间点与对照组相比显著升高,而血液中ALT除C、D组个别时间点外其余的均未有显著变化。B、C、D、E 4组肝脏中的碱性磷酸酶(ALP)相对A组均发生了显著下降,但C、D、E组与B组除个别时间点外均未有显著差异,因此肝脏中的ALP变化可能是无水乙醇作用的结果,而非IVM。血液中ALP则均未有显著变化。研究表明高剂量的IVM对吉富罗非鱼的肝脏造成了一定影响,因此在实际使用过程中应选择合适的给药方式以及合理的给药剂量。     

不同价态铬在不同水分条件下的生物有效性及其对水稻的毒性

氧化还原过程在铬的形态转化中起了重要作用,而铬形态的转化能够影响其生物有效性及毒性。通过温室土培试验研究了六价铬(Cr(Ⅵ))与三价铬(Cr(Ⅲ))在淹水与不淹水条件下在土壤溶液中的动态变化及水稻对其吸收的变化。结果表明,土壤中添加Cr(Ⅲ)时,土壤溶液中检测不出Cr;而随着土壤中添加Cr(Ⅵ)浓度的增加,土壤溶液中Cr(Ⅵ)的浓度增加,但是溶液中检测不出Cr(Ⅲ);淹水处理总体上降低了土壤溶液中Cr(Ⅵ)的浓度。而土壤添加Cr(Ⅲ)、Cr(Ⅵ)和水分处理对土壤溶液p H没有显著影响,p H在7.08.0之间变动。土壤添加Cr(Ⅵ)处理的水稻中,只有90 mg·kg-1Cr(Ⅵ)淹水处理的水稻成活,而其余处理水稻没有成活。土壤中添加Cr(Ⅲ)处理,水稻幼苗生物量随Cr(Ⅲ)浓度的增加而显著降低;除了200mg·kg-1Cr(Ⅲ)处理外,其余淹水处理的水稻幼苗生物量明显高于不淹水处理的。土壤添加Cr(Ⅲ)处理的水稻,在不淹水条件下水稻空壳率比较高,淹水条件下,随着土壤中添加Cr(Ⅲ)浓度水平的增加,水稻各部位Cr含量有增加的趋势,但增加不显著,秸秆最高Cr含量达到33.80 mg·kg-1,籽粒中Cr含量最高0.30 mg·kg-1。土壤固定Cr(Ⅲ)的能力远强于Cr(Ⅵ),添加Cr(Ⅵ)处理的土壤溶液中Cr(Ⅵ)的浓度很高,对水稻表现出较强的生长抑制。     

全氟辛烷磺酸（PFOS）对小鼠T、B淋巴细胞增殖功能和NK细胞活性的干扰效应研究（Disturbance of Mice Lymphocyte Proliferation Function and NK-cell Activity by Perfluorooctane Sulfonate（PFOS）Exposure）

为初步探讨全氟辛烷磺酸(Perfluorooctane sulfonate,PFOS)的细胞免疫毒性,采用每天1次经口灌胃染毒的方法,研究了PFOS经口重复剂量染毒对C57BL/6小鼠淋巴细胞增殖功能和NK细胞活性的影响.选择雄性C57BL/6小鼠40只,随机分为4组.实验组PFOS染毒剂量分别为5、10、20mg·kg-1(bw),对照组给予2%Tween-80.每天1次经口灌胃染毒7d后,制备脾脏T淋巴细胞悬液,以刀豆蛋白A(ConA)和大肠杆菌脂多糖(LPS)作为刺激源,采用MTT法检测T、B淋巴细胞增殖功能,乳酸脱氢酶释放法检测NK细胞活性.结果表明,10mg·kg-1和20mg·kg-1PFOS染毒组小鼠体重呈明显的下降趋势,且小鼠胸腺和脾脏指数显著低于对照组(p<0.05),而各PFOS染毒组小鼠肝脏指数均显著高于对照组(p<0.05).PFOS各染毒组T淋巴细胞的增殖功能均显著低于对照组(p<0.05);10mg·kg-1和20mg·kg-1PFOS染毒组小鼠NK细胞的活性显著降低(p<0.05).研究结果显示,PFOS暴露可降低小鼠淋巴细胞增殖功能和NK细胞活性,表明PFOS具有免疫抑制效应.     

Crop demand of manganese

The objectives of this study were to evaluate some of the popular rotation crops grown in Hungary for tolerance to low external Mn(2+) levels and to determine the critical tissue concentration of Mn(2+) deficiency during early stages of growth. The minimum Mn(2+) concentration required in soil nutrient contents was 42.5 mg kg(-1) for sunflower, 24.3 mg kg(-1) for tobacco and 10.2 mg kg(-1) for triticale. Sunflower, tobacco and triticale achieved optimum growth at 48.0-65.0 mg Mn(2+) kg(-1), 24.9-32.1 mg Mn( n+) kg(-1) and 28.7 to 29.6 mg Mn(2+) kg(-1), respectively. Critical shoot Mn(2+) concentration at early stages of growth was 53.6 mg kg(-1) in sunflower, 458.0 mg kg(-1) in tobacco and 193.8 mg kg(-1) in triticale. Our results demonstrate that the tolerance to low external Mn(2+) (triticale: <30.2 mg kg(-1); sunflower: <56.2 mg kg(-1); tobacco: <69.3 mg kg(-1)) and the critical tissue Mn(2+) levels for deficiency varied significantly between crop species tested.     

Influence of selected insecticides on phosphatase activity in groundnut (Arachis hypogeae L.) soils

Selected insecticides, Chloropyrifos, Dichlorovos, Methyl parathion, Phorate and Methomyl, at concentrations ranging from 0 to 10 kg ha(-1) were tested for their non-target effects towards activity of phosphatases in two soils. In soil samples receiving 2.5 kg ha(-1) of the insecticides Dichlorovos, Phorate and Methomyl and also in soil samples receiving 5.0 kg ha(-1) of the insecticides, Chloropyrifos and Methyl parathion, the activity of phosphatase was significantly more at 20 days period of incubation and decreased progressively with increasing period of incubation.     

Degradation of benzo[a]pyrene in soil with arbuscular mycorrhizal alfalfa

Mycorrhizal and non-mycorrhizal alfalfa (Medicago sativa) was grown in pots containing soil artificially contaminated with various levels of benzo[a]pyrene (B[a]P) (0, 1, 10 and 100 mg kg(-1)). Soil and plants were sampled after 30, 40, 50, 60 and 90 days and compared with unlanted pots. The percentage of mycorrhizal root length colonized by Glomus caledoniun was not significantly affected by the addition of B[a]P up to 10 mg kg(-1) but was significantly lower at 100 mg kg(-1)B[a]P compared with low concentrations (p < 0.05). There was no difference in soil polyphenol oxidase and dehydrogenase activity among the controls and applications of 1 and 10 mg kg(-1) of B[a]P. However, enzyme activities were significantly higher at 100 mg kg(-1) B[a]P compared with the other three treatments, and there was no mycorrhizal effect. Over a period of 90 days the concentration of B[a]P in soil in which alfalfa was grown was significantly lower than in unplanted soil (p < 0.05). Degradation rates of B[a]P added at 1, 10 and 100 mg kg(-1) without G. caledonium were 76, 78 and 53%, and with mycorrhizal inoculation were 86, 87 and 57%. The degradation rate in unplanted soil was significantly lower than in planted soil, and was significantly higher in medium- and low-B[a]P treatments than in the high B[a]P concentration tested. There is a possibility of enhancement phytoremediation of PAHs in rhizosphere soil with arbuscular mycorrhizal fungi.     

Effect of fenvalerate technical grade on acetyl cholinesterase activity in Indian bullfrog Haplobatrachus tigerinus (Daudin)

Indian bullfrog Haplobatrachus tigerinus (Daudin) was exposed to sublethal dose (1/3 of LC50 I.E. 1.166 mg/kg) of fenvalerate technical grade and the effect was studied on the specific activity of acetyl cholinesterase in the different tissues of frog viz., brain, muscle, liver, kidney and testis at different time periods viz., 3,6, 12, 24, 48 and 72 hours. The inhibition of specific activity of acetyl cholinesterase was in the order of kidney > brain > muscle > liver > testis. A significant inhibition was noticed in kidney at 12 hours (-64.33%) and no effect was noticed at 3 hours in testis (+0.67%). The AChE activity was inhibited in first three hours of administration of fenvalerate in all the tissue tested. The inhibition continued upto 6 hours or 2 hours in different tissue but the recovery was started by 24 hours and almost completed by 72 hours.